Cold cathode field emission devices (FEDs) are known in the art. FEDs typically comprise an electron emitter, for emitting electrons and an extraction electrode, for providing an electric field to the electron emitter to facilitate the emission of electrons. FEDs may also include an anode for collecting emitted electrons.
Operation of FEDs usually includes operable coupling a voltage between the extraction electrode and a reference potential and operable connecting the electron emitter to the reference potential. Alternatively, the extraction electrode may be operable coupled between the electron emitter and the reference potential. In order to effect modulated electron emission it is possible to provide an extraction electrode potential in concert with a variable electron emitter potential.
A common operational shortcoming of FEDs is that the electron emission occurs during the period of application of modulating signals only. Attempts to overcome this shortcoming have not been operationally enabling.
Accordingly, a need exists for a method of operating electron's emission independing in parts or all from technical date of field emission cathodes and enabling to operate flow of electrons in vacuum.
Field emission vacuum microtubes are also known. Vacuum tube technology typically relied upon electron emission as induced through provision of a heated cathode. More recently, solid-state devices have been proposed wherein electron emission activity occurs in conjunction with a cold cathode. The advantages of the latter technology are significant, and include rapid switching capabilities and resistance to electromagnetic pulse phenomena.
Flat panel field emission displays are also known in the art. The displays typically include electron emitters emitting electrons, extraction electrodes, proximally disposed with respect to the electron emitters, and anodes for collecting at least some of any emitted electrons with a layer of cathodoluminescent material (phosphor) that is deposited on the back side of the viewing area of the display.
Notwithstanding the anticipated advantages of solid-state field emission devices, a number of problems are currently faced that inhibit wide spread application of this technology. One problem relates to unable manufacturability of such devices. Current non-planar configurations for these devices require the construction, at a microscopic level, of emitter cones, through a layer by layer deposition process, is proving a significant challenge to today's manufacturing capability. Planar configured devices have also been suggested, which devices will apparently be significantly easier to manufacture. Such planar configurations, however, will not necessarily be suited for all hoped for applications.
Accordingly, a need exists for the FEDs that can be readily manufactured using known manufacturing techniques, and that yields the devices suitable for application in a variety of uses. Fabrication of the FEDs is also known and has, in general, led to nonuniform geometry of individual emitting cathodes in device arrays. Since electron emission is from the emitting cathodes, the non-uniform geometry of the individual emitting cathode typically causes non-uniform emission of electrons and, hence destruction of emitting cathodes that emit excess electrons.
There is a need for method that provides for minimizing non-uniform electron emission from emitting cathodes.